Household appliances are becoming increasingly complex as efforts are made to improve the efficiency and operational capabilities of the appliance. As used herein, "household appliances" refers to devices such as clothes washers, clothes dryers, dishwashers, cooking ranges, microwave ovens, and refrigerators that have electrical control of at least some functions of the device. Such household devices are typically independent units such that they can be fabricated and said independently of the building structure in which they are to be used.
Improved appliance efficiency is desired in order to reduce energy consumption (such as the electrical power to operate a refrigerator, clothes dryer, cooking range, or the like) and other resource consumption, such as reduction of water consumption in clothes washers and dishwashers, Electronic control of appliances has been used to improve efficiency through the use of sensors to monitor appliance performance and to provide data to adjust the appliance operating components to function in accordance with a desired operating profile (e.g., temperature sensors to improve refrigeration system operation, or water sensors to detect water cleanliness in dishwashers).
Conventional appliance manufacturing techniques have involved the routing of electrical wiring between a power supply (such as a junction attached to the power cord) and respective elements in the appliance that required the power. Most appliances with electronic control systems have included similar wiring arrangements, that is, direct connections between the appliance controller and the disparate sensors and actuators, resulting in a "star" type of wiring arrangement. All of the wiring in such systems has typically been relatively heavy gage (e.g., 18 gage or heavier) because the systems commonly rely on analog communication, with attendant higher voltage or current requirements, and for reasons of ease of fabrication (the wiring must withstand the many manipulations necessary to route it through the appliance in the assembly-line environment). As the sophistication of the control system (e.g., dependent on the number of options selected by the consumer on a particular appliance, and on the sensors and systems used to enhance energy and resource efficiency) increases, the amount of wiring and the time to install the wiring increases.
Such assembly techniques present difficulties with regard to resources used in production, such as the wiring to connect each sensor or actuator to the controller, the time to install the wiring, and the necessity of having unique wiring protocols for each appliance with different options or configurations. Further, as the number of wire interconnects increases, there is an increased probability of failure of some portion of the wiring for appliance control system.
In a household appliance it is desirable to reduce the total amount of wiring used for control system sensors and actuators as much as feasible while retaining operational reliability. Fabrication efficiency is also enhanced to the degree that standard wiring protocols can be used for a wide range of products.